Help! ID this electrical component.

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Dr88

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About 99% done installing a new harness in a 1990 Suburban, and came across this small grey box with a circuit inside. It has the letters FEDCBA where 6 wires come out, which seems to be the same as the ALDL connector. 2 of the wires (Tan/BLK, and BLU/WHT)seem to go to the ECM, but the other wires Tan,Tan,PPL,BLU don’t look like they connect anywhere.

I have searched every page in the electrical diagrams, and can’t seem to find this module anywhere, please help me ID this.
 

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Dr88

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I did find thiese pics but 1 is the ECM which is already installed? Possibly it’s (2) daytime running lamps?
 

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1998_K1500_Sub

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I’m confused.

Is this “new” harness you speak of an identical replacement?

Where did this “box” come from?

- Was this box OE on the 1990 Suburban you mentioned, and you are now trying to reinstall it with this new harness? Or,…

- Did the box come as part of the replacement harness? Or,…


Please fill in the blanks.


You also said “2 of the wires (Tan/BLK, and BLU/WHT) seem to go to the ECM”. How did you come to this conclusion?
 
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Dr88

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Sorry, It Was in with the old stock harness I removed. The new harness I installed came off another 1990 v1500 Suburban Silverado from the salvage yard, the old one was melted by the previous owner.
 

618 Syndicate

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A couple of things to mention.
A 1990 Suburban is a square body. Power train is similar to a gmt400 but body stuff is different.
DRLs didn't appear in usdm GM trucks until 96 or 97.
 

Dr88

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The doner Suburban did have marker/running lamps on the roof. I may have mixed the part in with the old stuff when I laid everything out.
 

1998_K1500_Sub

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Sorry, It Was in with the old stock harness I removed. The new harness I installed came off another 1990 v1500 Suburban Silverado from the salvage yard, the old one was melted by the previous owner.

So you made no note, when you removed it, of its electrical connections and mounting location. Is that correct?
 

1998_K1500_Sub

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You also said “2 of the wires (Tan/BLK, and BLU/WHT) seem to go to the ECM”. How did you come to this conclusion?

Pop the tabs on its plastic case and look inside. Post pictures.
 

Dr88

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So you made no note, when you removed it, of its electrical connections and mounting location. Is that correct?
Yes, unfortunately. I seem to remember it was with the “old” harness which also had a brake booster for trailering.
 

Dr88

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You also said “2 of the wires (Tan/BLK, and BLU/WHT) seem to go to the ECM”. How did you come to this conclusion?

Pop the tabs on its plastic case and look inside. Post pictures.
There were two wires coming off the ECU connector with the same colors.
 
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